ABSTRACT: Adenosine triphosphate-binding cassette transporter A1 (ABCA1) plays an important role in lipid metabolism and is involved in diabetes. We investigated the associations between lipid profiles and an early-onset diabetic phenotype with ABCA1 genotypes among 999 type 2 diabetes mellitus patients in the Han Chinese population of Taiwan. During study enrolment, blood samples were collected by venipuncture from these patients for genomic DNA isolation and serological tests, and data related to the diabetes age of onset were collected using a self-report questionnaire. Four single-nucleotide polymorphisms (SNPs) were selected for genotyping by polymerase chain reaction in each patient. The present study found that the high-density lipoprotein (HDL) levels were significantly different among patients with different genotypes at SNP rs2487039 (p=0.018). The body mass index (BMI) was also significantly different among patients with different genotypes at SNP rs2487039, rs2230806, and rs200069 (p=0.009, 0.004, and 0.003, respectively). The polymorphisms at position rs10121901 in ABCA1 were statistically associated with development of early-onset type 2 diabetes mellitus (p=0.013), with an odds ratio of 0.78 (95% confidence interval: 0.64–0.95). In conclusion, an ABCA1 variant is associated with HDL level, BMI, and early-onset type 2 diabetes mellitus in a specific Taiwanese population.